notes on ileticularian rhizopoda. 277 



Globigerinida. 



The Globigerinida form a large and diverse group, and 

 almost every section of it acquires some fresh significance 

 from the "Challenger" collections. Of the simple non-septate 

 genus Spirillifia several new forms are now to be described. 

 The genus Chilostomella, first found in the recent condition 

 two or three years ago by the Rev. A. M. Norman, is shown 

 by the '^ Challenger " dredgings to have a wide distribution 

 as a living type, and its near ally, Allomorphina, aforetime 

 regarded as a rare Cretaceous and Early Tertiary fossil, is 

 represented by recent specimens from two to three localities. 

 Pavonina, concerning which little or nothing has been 

 known beyond its general external appearance as depicted 

 by d'Orbigny, is met with at two or three stations, and the 

 difficulty which has been experienced by later Rhizopodists 

 as to its zoological affinity is found to have arisen from the 

 inaccuracy of the original figures. Of the Rotaline genera 

 it is difficult to speak briefly, the number of species obtained 

 is so large. Probably the result of their examination will 

 be of value rather in the more accurate definition and better 

 understanding of forms already known and named than in the 

 number of new species to be described. There are, however, 

 a few very distinct forms not previously recorded. Of these, 

 two som.ewhat important Puhinulina'^ have already been 

 noticed, the published descriptions being founded upon 

 " Challenger" specimens, and a striking little PlanorhuUna 

 is described and figured in the present paper. 



Of the genus Gloh'ujerina and its immediate allies a some- 

 what longer summary is needful — one that may serve as the 

 basis of a subsequent detailed exposition of so important a 

 group — and to this end certain new species, of which illus- 

 trative figures cannot at present be given for want of space, 

 are introduced, as Avell as circumstances permit, by verbal 

 descriptions. 



Genus— ^Y\^\\AA^k,Ehrenherg. 



The genera Spirillina, Co7'nuspira, and Ammodiscus, are 

 isomorphous, and represent vitreous, porcellanous, and are- 

 naceous types of structure respectively. The resemblance of 

 the tests of some of these simple forms to the shells of 

 pteropods and annelids, whilst often a source of difficulty 

 where the imperforate Cor?iuspira and the sandy Afnmodisctis 

 are concerned, scarcely affects the diagnosis of Spirillina, 



" Pulvim(limfi(vics,a.nd P. Menardii, var. tumid(t'"(j&o\. Mag.,' 1877, 

 Dec. 2, vol. iv, p. 535. 



VOL. XIX. — NEW SER. T 



